Process for the production of a salt of the laevulinic acid derivative of cyanacetic acid hydrazide



United States PROCESS FOR THE PRODUCTION OF A SALT OF atent THE LAEVULINIC ACID DERIVATIVE OF CY- V sesses the disadvantage of not being soluble in water to the desired extent. Salts of this hydrazone are not known from literature.

It has now been found that well water-soluble salts of the aforesaid hydrazone can be obtained by reacting either the laevulinic acid derivative of cyanacetic acid hydrazide with piperazine, piperazine hydrate or piperazine-yielding agents in solution, or by reacting the piperazine salt of laevulinic acid with cyanacetic acid hydrazide. A salt is thus obtained of the general formula.

It is obvious that the hydrazone of cyanacetic acid hydrazide and laevulinic acid can be brought into concentrated aqueous solution by means of agents such as caustic soda, sodium carbonate or bicarbonate, calcium carbonate, ammonia or simple aliphatic amines. In attempting to convert salts thus produced in a uniformly crystallized form, there are however, mostly obtained hygroscopic or viscid products or, as in the case of the calcium salt, a crystallized product which, with a water solubility of only does not meet veterinary requirements.

On the other hand the piperazine salt of the laevulinic acid derivative of cyanacetic acid hydrazide can easily be obtained in a crystallized form. The salt is not hygroscopic, but posses a high Water solubility which permits the production of 35% solutions at room temperature.

Moreover the piperazine salt of the aforesaid hydrazone is more eifective than the cyanacetic acid hydrazide, as is apparent from the following table.

Cattle infected with lung worms were divided according to their degree of sickness, into four groups (group number in column 1; description of the degree of sickness in column 2 of the table). Of each group, a number of animals were treated with the piperazine salt of laevulinic acid derivative of cyanacetic acid hydrazone and after 14 days the percentage of the animals not excreting any lung worm larvae was determined (column 3,057,866 Patented Oct. 9, 1962 3 of the table). Apart from the examination of the general state of the animals, freedom from larvae in their excreta is an objective measure for the success of the treatment.

From each group a further number of animals were then treated three times with cyanacetic acid hydrazide for comparison. The percentage of the parasitologically cured animals, i.e. those which did not excrete larvae any more in their excreta after 14 days, are given in column 4.

Percentage of the parasitologically cured animals Column 2 Column 3 Column 4 Division of the Column 1 animals according Treated twice with Treated 3 times to the degree of 60 mg./kg. of the with 20 mgJkg. of

clinical illness piperazine salt of the cyanacetic the laevulinic acid acid hydrazide derivative of cyanacetic acid Hydrazide Group N o.:

(l) Larvae excreted 87 78 without clinical illness.

(2). Slightly ill 80 46 (3). Average illness 31 (4).--. Very ill 7O 12 For an exact evaluation of the therapeutic result groups No. 3 and 4 play the principal part (those ex creting larvae without clinical symptoms and the slightly ill animals are only conditionally evaluatable, since good feeding and stabling in most cases achieves self-curing).

Twice treatment with the compound produced according to the invention thus leads in 90 or 70% of cases to curing whereas triple treatment with the comparison substance only leads in 31 or 12% of cases to curing.

The following examples are given for the purpose of illustrating the invention.

Example 1 98.5 g. of the laevulinic acid derivative of cyanacetic acid hydrazide suspended in 250 cc. of alcohol are treated with 48.5 g. of piperazine hexahydrate and heated to 40 C. until dissolved. The anhydrous salt (111 g.) filtered otf with suction after cooling melts at 132 C. with decomposition. It is obtained very pure and can be isolated free from water of crystallisation or in the form of its dihydrate.

CzoHaaOaNa Percent C Percent H Percent N Example 2 19.7 g. of the laevulinic acid derivative of cyanacetic acid hydrazide suspended in 70 cc. of hot alcohol, are treated with 4.3 g. of piperazine-monohydrate. The resulting clear solution is filtered and separates after cooling 21.3 g. of the anhydrous salt of melting point 129l31 C. with decomposition.

Example 3 11.6 g. of laevulinic acid dissolved in 50 cc. of hot alcohol, are treated with 4.3 g. of piperazine and then with 9.9 g. of cyanacetic hydrazide. To the clear solution there are added 50 cc. of benzene. After 3 hours 23.7 g. of the salt are filtered off with suction as the dihydrate, which decomposes at 118-120 C.

The alcohol may be replaced by the corresponding amount of methanol.

Example 4 To a solution of 36.5 g. of piperazine monoacetate in 350 cc. of methanol there is added a suspension of 98.5 g. of the laevulinic acid derivative of cyanacetic acid hydrazide in 300 cc. of methanol. The mixture is heated to 60 C. for some minutes. After cooling 78 g. of the pure salt are obtained.

We claim:

1. Process for the production of a salt of the laevulinic acid derivative of cyanacetic acid hydrazide, which comprises reacting a member selected from the group consisting of (1) the laevulinic acid derivative of cyanacetic acid hydrazide and (2) the piperazine salt of laevulinic acid with a member selected from the numbered group consisting of, respectively, (1) piperazine, piperazine hexahydrate, piperazine monohydrate and piperazine salts; and (2) cyanacetic hydrazide; and provided that the reactant members are selected from correspondingly numbered groups.

2. A compound of the formula CH3 NG-CHr-OONH-N=J3--(CH2)z-COOH N CH3 H wherein X is a number from O to 2 inclusive.

3. Process that comprises reacting the laevulinic acid derivative of cyanacetic acid hydrazide with piperazine hexahydrate to form the corresponding piperazine salt of said laevulinic acid derivative of cyanacetic acid hydrazide.

4. Process that comprises reacting the laevulinic acid derivative of cyanacetic acid hydrazide with piperazine monohydrate to form the corresponding piperazine salt of said laevulinic acid derivative of cyanacetic acid hydrazide.

5. Process that comprises reacting the piperazine salt of laevulinic acid with cyanacetic acid hydrazide to form the corresponding piperazine salt of the laevulinic acid derivative of cyanacetic acid hydrazide.

6. Process that comprises reacting piperazine monoacetate with the laevulinic acid derivative of cyanacetic acid hydrazide to form the corresponding piperazine salt of said laevulinic acid derivative of cyanacetic acid hydrazide.

References Cited in the file of this patent UNITED STATES PATENTS 

1. PROCESS FOR THE PRODUCTION OF A SALT OF THE LAEVULINIC ACID DERIVATIVE OF CYANACETIC ACID HYDRZIDE, WHICH COMPRISES REACTING A MEMBER SELECTED FROM THE GROUP CONSISTING OF (1) THE LAEVULINIC ACID DERIVATIVE OF CYANACETIC ACID HYDRAZIDE AND (2) THE PIPERAZINE SALT OF LAEVULINIC WITH A MEMBER SELECTED FROM THE NUMBERED GROUP CONSISTING OF, REPECTIVELY, (1) PIPERAZINE, PIPERAZINE HEXAHYDRATE, PIPERAZINE MONHYDRATE AND PIPERAZINE SALTS; AND (2) CYANACETIC HYDRZIDE; AND PROVIDED THAT THE REACTANT MEMBERS ARE SELECTED FROM CORRESPONDINGLY NUMBERED GROUPS. 